Stuart_Armstrong comments on A proposed inefficiency in the Bitcoin markets - Less Wrong

3 Post author: Liron 27 December 2013 03:48AM

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Comment author: Liron 31 December 2013 08:03:25AM 0 points [-]

Hm, pretty sure your logic doesn't make sense here.

By your logic, Euros/Dollar, Yen/Dollar, and other currency prices would also be random walks on a log scale. But I don't believe they are.

I think the reason Bitcoin is a log-scale random walk is that people's beliefs about BTC's Expected Value is Fermi-estimate-like.

And I think the only reason stocks and other standard exponentially-increasing investment vehicles are exponentially increasing, is because they entitle you to a constant fraction of the exponentially-increasingly-valuable economy.

Comment author: Stuart_Armstrong 31 December 2013 12:13:48PM *  1 point [-]

And I think the only reason stocks and other standard exponentially-increasing investment vehicles are exponentially increasing, is because they entitle you to a constant fraction of the exponentially-increasingly-valuable economy.

Exponential increase is a consequence of the fact you don't have enough capital to exhaust investment opportunities or affect the market (much). Suppose I can buy G for £100, which will give me £110 at the end of the year. Then I can buy 2G, or 3G, or xG, giving me £x110 at the end of the year. So my profit is always proportional to my capital (as long as my capital isn't too large), so exponential growth of investment is the natural state of being.

Add uncertainty, and you get the random walk on a log scale (that's a little bit more subtle, and needs some other assumptions, but the fundamental argument is similar).

Comment author: Liron 02 January 2014 10:57:13PM *  0 points [-]

Your explanation is consistent with mine but is more reductionist. Thanks.